1. Field of the Invention
The invention relates to electrochemical current sources, specifically air-metal electrochemical aluminum systems suitable for electronic devices, including radio telephones, portable audio and video players, video cameras, and personal computers.
2. Description of the Prior Art
There are known current sources, which contain a series of basic components including a cathode, an anode, and an electrolyte, as well as a current converter with a stabilizer. In U.S. Pat. No. 5,656,876, a battery pack of lithium solid state cells is shown, where a DC/DC converter provides a stable operating voltage, possibly also different voltages upon request. U.S. Pat. No. 5,286,578 (shows a flexible electrochemical cell having an air cathode, a metallic anode and an electrolyte chamber. The electrolyte chamber is collapsed, when the battery is shipped (without electrolyte) to save space. U.S. Pat. No. 5,554,918 shows a mechanically-rechargeable battery having a replaceable zinc anode, an air electrode (one option) and a housing. A non-spillable electrolyte is contained in the housing. When necessary, the anode can be removed and replaced with a fresh anode. Further related battery art is found in U.S. Pat. No. 5,424,147, U.S. Pat. No. 3,798,527, U.S. Pat. No. 3,876,471, U.S. Pat. No. 5,525,895, U.S. Pat. No. 5,415,949, U.S. Pat. No. 5,049,457, U.S. Pat. No. 4,925,744 and U.S. Pat. No. 6,025,694.
Different additions to an aluminum anode, used in aluminum batteries, and to the electrolyte of such batteries are disclosed in U.S. Pat. No. 5,032,474. Preferred elements for the aluminum alloy composition are Cd, Sn, Bi, Sb, In, Ge, B, Se, Te, P, As, C, Re, Pd, Nb, Si and Zn in concentrations between 0.005% and 1.0% (by weight). As an example, Sn present in binary Al alloys should range from 0.01% to 0.5%, optimally 0.02%. The electrolyte is specified as alkaline, having one or more of the elements used for the Al alloy. In U.S. Pat. No. 5,004,654, an aluminum battery is shown, which has an anode comprising Al with Mg and/or Ca and optionally also In. Sn is present either in the electrolyte or in the anode or both. No Ga is present in the anode. Further related battery art is found in U.S. Pat. No. 5,004,654, U.S. Pat. No. 4,554,131 and U.S. Pat. No. 4,906,535.
Still further background material can be found in L. l., Antropov, E. M. Makushina, V. F. Pinasenko. Inhibitors of the Corrosion of Metals. xe2x80x94Kiev, xe2x80x9cTekhnikaxe2x80x9d, 1981. xe2x80x94184pg., N. D. Tomashov. The Theory of Corrosion and Protection of Metals. xe2x80x94Moscow, Academy of Sciences of the USSR, 1959., The Products of Science and Technology. The Theory of Corrosion and Corrosion Protection. Vol.9, Moscow, VINITI, 1982. xe2x80x94256 pg., V. V. Scorcelletti. Theoretical Background of Metal Corrosion. xe2x80x94Leningrad, xe2x80x9cKhimiyaxe2x80x9d, 1973. xe2x80x94265 pg., and A. L. Rotinyan. Theoretical Electrochemistry. xe2x80x94Leningrad, xe2x80x9cKhimiyaxe2x80x9d, 1981. xe2x80x94423 pg.
These known structures, however, have certain apparent disadvantages including:
a limited time of uninterrupted power and the necessity of periodic recharging the electric grid using a special recharging device;
lowering of the electric load at the rest cycle;
use of non-renewable sources of raw materials;
the formation of ecologically harmful waste products;
high cost;
low mass-energy characteristics;
high self-discharge rates;
high environmental impact (difficult to recycle/heavy metals);
low energy resource.
The goals of the present invention include:
providing an independent, self-contained, electrical source that can be mechanically recharged;
improving the performance characteristics by refusing of electric recharging;
increasing the time during which the electrical source will supply uninterruptable power during the conversation and waiting cycle;
providing an electrical power source that remains environmentally and ecologically clean throughout its full life cycle, including manufacture, use, and recycling or disposal;
lowering the cost of both manufacturing and usage.
These goals are achieved in the following manner:
The air-metal power source is made of the body containing a cathode and a replaceable unit (cartridge), containing anode and electrolyte. Thus power supply recharging is accomplished with mechanical recharging (by replacing the cartridge) and assuring a self-contained power source.
In the invention, a battery comprises at least one non-consumable gas diffusion positive electrode; at least one consumable negative metal electrode; an electrolyte based on water solutions of salts and/or bases; and a housing enclosing said electrolyte, said at least one positive electrode and said at least one negative electrode, to create an inter-electrode gap. The at least one negative electrode comprises a metal selected from the group consisting of aluminum, zinc, magnesium, and alloys thereof, and further comprises an effective amount of one or more additives selected from the group consisting of Ga, In, TI, Sn, Cd, Pb, Mn, and Fe, the effective amount of the additives improving the electrochemical characteristics of the at least one negative electrode, reducing corrosion, and preserves the at least one negative electrode while being stored.
The additives are preferably present in the following concentrations: Ga 0-5 mass %, In 0-5 mass %, TI 0-5 mass %, Sn 0-5 mass %, Cd 0-5 mass %, Pb 0-5 mass %, Mn 0-5 mass % and Fe 0-5 mass %.
The additives are more preferably present in the following concentrations: G a 0.01 mass %, In 0.5 mass %, TI 0.015 mass %, Sn 0.15 mass %, Cd 0.01 mass %, Pb 0.02 mass %, Mn 0.03 mass % and Fe 0.01 mass %.
The thickness of the at least one negative electrode is preferably in the range of 0.05 mm to 10 mm, and a volume of the electrolyte is selected to achieve balanced consumption during the discharge of the battery.
The electrolyte is preferably a salt solution, an alkali solution or a mixture of a salt solution and an alkali solution, the electrolyte further having an addition of Sn+4, Pb+4, Ga+3, In+3, poly-saccharide based on D-glucose, polyesters including amides, 2-3 C alcohols and halogenides/hydroxides of alkaline metals, to provide a decrease in anode corrosion during discharge, an increase in electric capacity of the electrolyte, a decrease of freezing temperature of the electrolyte, a change of chemical reaction results into microcrystalline form and stabilization of the electrolyte during storage.
The electrolyte advantageously comprises 0-30% KOH, 0-0.1 mol/l Sn, 0-0.1 mol/l Pb, 0-0.1 mol/l Ga, 0-0.1 mol/l In, 0-10 mass % D-glucose, 0-5 mass % alcohols, 0-5 mass % polyester and 0-20 mass % NaCl.
The electrolyte more preferably comprises 20% KOH, 0.06 mol/l Sn, 0.02 mol/l Pb, 0.01 mol/l Ga, 0.02 mol/l In, 5 mass % D-glucose, 2 mass % alcohols and 15 mass % NaCl.
The electrolyte alternatively comprises 0.02 mol/l Pb, 0.06 mol/l Sn, 0.01 mol/l Ga, 0.02 mol/l In, 5 mass % D-glucose, 2 mass % alcohols, 2 mass % polyester and 15 mass % NaCl.
The first unit further preferably comprises a porous matrixxe2x80x94electro-carrier, soaked in a composition based on a salt solution, an alkali solution or a mixture of a salt solution and an alkali solution, the porous matrixxe2x80x94electro-carrier further having an addition of Sn+4, Pb+4, Ga+3, In+3, poly-saccharide based on Dglucose, polyesters including amides, 2-3 C alcohols and halogenides/hydroxides of alkaline metals, to provide a decrease in negative electrode corrosion during discharge, an increase in electric capacity of electrolyte, a decrease of freezing temperature of the electrolyte, a change of chemical reaction results into microcrystalline form and stabilization of the electrolyte during storage.
The at least one positive electrode advantageously comprises additives selected from the group consisting of lead oxides and silver-indium alloys, to provide stabilization of properties during extended storage of the positive electrode and increase in electrochemical activity while the battery is in use.
At least one of the additives is advantageously incorporated into the at least one positive electrode comprising less than about 200 mg/cm3 of a total surface area of the at least one positive electrode.
The first unit preferably comprises at least one membrane, the membrane being permeable to hydrogen and impermeable to liquids.
The at least one positive electrode is advantageously provided with at least one fourth cavity, which is fillable with the electrolyte.
The inter-electrode gap is chosen to be the minimal possible based on construction consideration, and wherein a necessary reserve of the electrolyte is contained in at least one fifth cavity arranged in the first unit and in at least one sixth cavity arranged in the second unit.
The at least one negative electrode advantageously covers the at least one positive electrode in the shape of a pocket, the pocket being connected to surrounding atmosphere.
The at least one negative electrode is preferably substantially U-shaped and covers the electrolyte impermeable container.
The first unit further advantageously comprises a current converter, the current converter providing conversion of a direct current of the battery into an alternating current and stabilization of a voltage output by the battery.
The first unit further alternatively comprises a current converter, the current converter providing conversion of a direct voltage of the battery into a different level of voltage and stabilization of the voltage output by the battery.
The at least one negative electrode preferably comprises a hydrate metal oxide.
The at least one negative electrode alternatively comprises aluminum. The aluminium is preferably obtained following the Bayra process.
The at least one negative electrode preferably has a thickness of between 0.04 to 0.5 of a positive electrode spacing inside a volume of an active part of the second unit.
The battery further advantageously comprises a first unit, comprising the housing with the at least one positive electrode and the electrolyte, the electrolyte being held in an electrolyte impermeable container, and a second unit, comprising the at least one negative metal electrode and the electrolyte. The second unit is replaceably and sealingly arranged in the first unit, so that when the at least one negative electrode and the electrolyte are consumed, the spent second unit is removed and a fresh second unit is inserted instead of the spent second unit, and the electrolyte impermeable container is penetrated by a puncture means after the second unit has been fully inserted into the first unit, to allow the electrolyte to flow between the at least one positive electrode and the at least one negative electrode.
The battery further advantageously comprises at least one first conduit for connecting to and distributing ambient air, at least one second conduit for distributing the electrolyte, and at least one third conduit for collecting reaction products in cooperation with the at least one first conduit and the at least one second conduit.
The puncture element advantageously comprises a substantially U-shaped element having sharp ends, the puncture element being arranged inside the electrolyte impermeable container, and the battery further comprises a biasing means for pressing the electrolyte impermeable container against the sharp ends, to cause the electrolyte impermeable container to break.
The biasing means preferably comprises a thread, which is attached to the electrolyte impermeable container.
The biasing means alternatively comprises a push bar having a foot end, which contacts the electrolyte impermeable container.
The at least one positive electrode and the at least one negative electrode preferably form pairs of one positive electrode and one negative electrode, and the pairs are connected in series to produce a desired output voltage. Alternatively, the pairs are connected in parallel to produce a desired output current.
The first unit further advantageously comprises at least one first sealing means, forming a hermetic seal between the first unit and the second unit when the first unit and the second unit are engaged.
The second unit further preferably comprises at least one second sealing means, forming a hermetic seal between the first unit and the second unit when the first unit and the second unit are engaged.
Alternatively, the first unit further comprises at least one first sealing means and the second unit further comprises at least one second sealing means, the first sealing means and the second sealing means cooperating to form a hermetic seal between the first unit and the second unit when the first unit and the second unit are engaged.
The at least one positive electrode is preferably removably arranged in the first unit, to provide a possibility to replace the at least one positive electrode.
The battery further advantageously comprises a cap portion, the cap portion comprising a third sealing means and a releasable locking means, the third sealing means providing a hermetic seal between the first unit and the second unit, when the first unit and the second unit are engaged, and the releasable locking means is configured to maintain the body and the second unit in an engaged configuration until released.